The present invention relates generally to telephone ring detectors, and more particularly to telephone ring detectors which may be utilized as an interface between a telephone and stereo unit to generate a modulated tone into a headphone set of the stereo unit in response to an incoming telephone signal.
In recent years, manufacturing technology in stereo component systems has progressed to a point wherein the majority of the purchasing public utilize home stereo systems. This widespread use has resulted in both the leisure time listener as well as the avid audiofile demanding more sophisticated, low distortion, sound reproduction. To meet this performance demand, many listeners have begun utilizing stereo headphone sets which, due to their close proxmity and encapsulating position about the ears of a listener, permit the maximum stereo effect to be achieved with a minimum component equipment cost.
Although the use of stereo headphones significantly improves reproduction sound quality, it severely limits the awareness of the user to external audible stimuli, such as a telephone call. Thus, when listening to recorded music upon a headphone set, heretofore a user had to rely solely upon visual observation to be aware of external stimuli which, with respect to incoming telephone calls, was totally inadequate.
Although various telephone ring detector devices have recently been developed and made available in the marketplace, the majority of such ring detectors have been utilized exclusively in telephone answering circuitry wherein, upon detecting an incoming telephone signal, a prerecorded announcement is initiated and a message subsequently recorded from the calling party. As such, the prior art telephone ring detecting devices have not been utilized to alert an occupant of an incoming call, but rather to permit an incoming telephone call to be answered automatically without the presence of the user.
Additionally, the existing prior art detecting circuits have typically comprised high technology, sophisticated equipment which, due to its relatively high initial investment and maintenance costs, has been utilized primarily in commercial telephone applications. Further, such prior art detectors have been incapable of being adapted to provide an interface between conventional telephones and home stereo units. As such, there exists a substantial need for a relatively low cost stereo interface telephone ring detector which may be utilized to automatically alert a stereo listener of an incoming telephone call.